The Bicoloured Frog’s Wedding Suit

The polka dots had thinned into the skin. The blacks had greyed into sallower shades. But the red-rimmed eyes still gleamed like rubies. Here was the Bicoloured Frog again, dressed for its wedding party

Bicoloured Frog (Clinotarsus curtipes).
In early June this year, just as Agumbe awaited the deluge of the southwest monsoon, we visited the Agumbe Rainforest Research Station there. You might remember that we had posted an encounter with the polka-dotted Bicoloured Frog (Clinotarsus curtipes).
In his Book of Indian Reptiles and Amphibians, J C Daniel mentions that the species begins to breed with the onset of the southwest monsoon and tadpoles can be sighted in plenty in April, May and June. However, in Agumbe, none of the frogs we encountered displayed any hint of breeding colours.
The Kulgi Nature Camp abutting the Dandeli-Anshi Tiger Reserve (15°16’01″N 74°37’01″E), with its broad-leafed north Western Ghats moist deciduous forests, is drier than Agumbe (13°30’30″N 75°5’45″E) and the monsoon had receded by early October, though thundershowers staged a mock-charge in the evenings.
Agumbe, June: Bi-coloured Frog in non-breeding colours
The forest floor was not just a lot drier, the leaf litter was much less than at Agumbe
It was mid-morning and we were out birding along the Birder’s Trail near Kulgi Nature Camp, having just enjoyed watching a mixed hunting party — Velvet-fronted Nuthatch, Paradise Flycatcher, Scarlet Minivets, Brown-capped Pygmy Woodpecker, Greater Flameback and Common Iora — and a much-relieved Sandy commented on the uncharacteristic lethargy of the leeches (there was to be no nightmare-induced macabre storytelling tonight). And then a casual glance at the forest floor revealed this treasure.
Creamy yellow upper body with prominent black dots
The upper body is bright golden-yellow and the dots have almost faded off
The transformation was remarkable. The dots on the upper body had almost faded off and the yellow was much brighter — almost golden. The sharp division between the coloration of the upper and lower parts of the body remained but the glistening black limbs were now brown.
The black limbs have turned brown
The white patch that ran from the snout towards the eye was now yellow and a small black band separated it from the greenish-yellow (almost olive) skin of the sides, which now displayed a dual coloration — a change from the uniform black of the non-breeding form. The most remarkable change, however, was the white-blotched grey of the frog’s underside and the lower half of the belly between the fore and hind-limbs. It gave the frog’s underbelly and sides a rather lichen-patched texture (less on the underbelly than the sides of the lower belly), perhaps a useful camouflage from slithering predators on the forest floor.
The large red-rimmed eye still glowed like a ruby.
Notice the lichen-patched texture of the underbelly that was uniform black before breeding commenced
Behaviourally the frog did not seem to have changed much. It was solitary, did not call, and was not jumpy or nervous. While we photographed, it stayed put, only taking a single jump if we stepped too close.
It did seem a bit late in the season, but the forest had several wet patches and we hoped that somewhere, not too far away, was another individual of the species. Of the opposite sex.
Text and photographs by Sahastrarashmi

Posted from Dandeli, Karnataka, India.

Encounter: Bombay Caecilian, an amphibian epiphany

Its serpentine structure and moist, clammy skin gives the caecilian the appearance of a frog masquerading as a snake. Chances are you’ve seen this intriguing amphibian before but never taken a second look at it!
The head of the Bombay Caecilian, showing the tiny tentacles, mouth and the eyes. Note the ring-like folds on the skin and the whitish secretion of mucus
During our three days at the Agumbe Rainforest Research Station, breakfast conversations with station manager Prashant always yielded something interesting. On the morning of the day we were leaving I asked him casually about his work, and he mentioned in his characteristic unassuming manner that he had been part of the discovery and documentation of some species of Caecilians.
Caecilians! My ears perked up at the word. I hadn’t heard it in a long time and something told me we were very close to an epiphany of sorts.
“Aren’t they legless amphibians?” I asked.
“Yes,” he said laconically.
“And do you get them around here?”
“Yes.”
“Wish we could see them…” I murmured hopefully.
“I could show you one,” he said helpfully. “I have a pet.”
For the rest of the day we were at our best behaviour, grinning and glancing at Prashant hopefully every time we passed him. After lunch he asked us to wait outside a hut that probably served as a storage room for specimens. In its dim murkiness we saw him digging around in a bucket.
The caecilian’s sinuous movements are very like a snake’s

He came out of the hut holding a slender, purplish-black creature that resembled a snake at first glance. But unlike a snake’s skin, which is dry and scaly, this animal’s shiny body surface appeared to secrete mucus that rubbed off in white gobs on Prashant’s hands. He invited me to touch it, and the skin felt soft, cool, slippery and moist under my fingertips. It was like touching a frog masquerading as a snake. This mucus is believed to be mildly toxic to predators, though that doesn’t prevent pigs, snakes and chickens from eating some of the smaller caecilians.

Mucus, secreted by the caecilian’s skin, keeps it moist while its mild toxicity is thought to deter predators
Though their snakelike appearance can be deceptive, caecilians are legless amphibians related to frogs, toads and salamanders. Their serpentine body structure is an adaptation for a burrowing lifestyle. They live among leaf litter and loose soil and can be found under fallen trees and rocks. There are 26 recorded species of caecilians in India, of which 25 are endemic and about 20 of these are found in the Western Ghats. Other caecilians have also been discovered from forests in Manipur and Nagaland in northeast India.
The species we were admiring was the Bombay Caecilian (Ichthyophis bombayensis), which occurs in the Western Ghats. It was nearly a metre long – I had expected caecilians to be much smaller — and the body is annulated (the skin is ringed with folds) as in worms. The two tiny eyes, barely more than dark spots sheathed by skin, are surrounded by pale white rings. This caecilian’s eyesight is perhaps limited to distinguishing between darkness and light. The mouth has rows of small teeth that are adapted for holding and cutting prey, which primarily consists of earthworms, termites and small invertebrates that live in the soil. There are two tentacles close to the mouth and this has perhaps given rise to the myth that these are venomous two-headed snakes — in Kerala they are known as iruthalamoori (literally, two-headed bullock) and killed because they are commonly mistaken for snakes (some resemble the similarly coloured shieldtail snakes).

Snake in the grass? Sadly, many caecilians are easily mistaken for snakes and therefore killed

Caecilians are oviparous, which means they lay eggs. It’s hard to tell males and females apart externally, but males have a concealed copulatory organ, the phallodaeum, which can be inserted like a pseudo-penis into the aperture of the female during copulation. Fertilization takes place inside the female’s body. As with most amphibians, caecilian eggs are strung together in gelatinous threads, like beads in a necklace. The female caecilian protects her clutch of eggs by coiling her body around them. The larvae are aquatic and free-swimming — like tadpoles.

If you happen to visit a plantation of areca, banana or coffee with moist, humus-rich soil and compost pits, look out for caecilians. Just remember that like all amphibians they are highly sensitive to depletion of soil quality and are therefore important environmental indicators.

Prashant treats us to a ampbibian epiphany

As we watched the caecilian with fascination, Prashant put it down on the ground. It moved swiftly through the grass and began looking for a place to hide away from the sunlight. He then put it back in its bucket and announced, “Show is over!”

Thanks, Prashant. We’re all really grateful to you for introducing us to this intriguing amphibian. We have one more reason to keep our eyes glued to the ground in a rainforest. The birds can wait!

References:
A Field Guide to the Caecilians of the Western Ghats, India by Gopalakrishna Bhatta, Department of Zoology, Sri JCBM College, Sringeri, India

Text and additional photos: Beej
Lead photos: Sahastrarashmi
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The Green Ogre – Birds, Wildlife, Ecology and Nature notes from India.

Posted from Agumbe, Karnataka, India.

Encounter: Golden Frog

Our very own Golden Frog, a Western Ghats endemic, gave us the cherished privilege of a long and uninterrupted audience

 

At the outset let me state that the frog we encountered is not to be confused with the Panamanian Golden Frog (Atelopus zeteki), which was last seen and filmed in the wild in 2007. The entire known population in the wild is now assumed extinct and the frog survives only in captivity. Our Golden Frog (Hylarana aurantiaca) is luckier, but the Sword of Damocles of the amphibian world, the fungal infection chytridiomycosis, hangs over it;s head too.

Frogs have an extremely permeable skin, through which they can absorb oxygen into the bloodstream. Oxygen first dissolves in a thin water film on the surface of the skin and then from there into the blood. This feature, which evolved to aid their amphibious lifestyle, is now one of the reasons for the rapid decline of frog populations around the globe. The permeable skin makes them highly susceptible to toxins in the water. So evolved is this feature in frogs that a lungless frog has been discovered in 2007 in the rainforests of Borneo, Indonesia. The Bornean Flat-headed Frog (Barbourula kalimantanensis) has no lungs and this 7 cm long frog breathes entirely though its skin. The absence of lungs helps it attain a flatter body shape — a key adaptation to survival in its habitat, fast-running mountain streams, since it aids streamlining and reduces drag. But it is already threatened due to rise in water toxicity due to mining.

We first encountered the Golden Frog during a late evening “frogging” session at ARRS. They were perched on leaves and calling (the vocal sac is internal) but in the feeble torchlight it was very difficult to make out the distinctive coloration, especially the yellow-orange back bordered by two golden streaks – the characteristics that gives them their regal name. The next day I saw a couple of them on the same bushes beside a small monsoonal wetland right outside our cottage and as the excited Ogres scanned the bushes we realized that there at least 20 of them right there. As we photographed them, the frogs maintained the calm and composure of meditating Zen monks. There was no alarm, no anxiety and no visible discomfiture. In fact, as the successive monsoon fronts arrived — the sequence of mist, drizzle, heavy shower, sunshine, mist played out though the day — they hardly seemed to move. I observed one of them seated in position for almost three hours. They also seemed to be quite gregarious, seated on leaves, twigs, stems and branches of the bush close to each other.

Hylarana aurantiaca is found in moist evergreen forests, swamps and coastal regions bordering the southern Western Ghats and is probably a Western Ghats endemic since the population found in Sri Lanka is suspected to belong to a separate, yet undescribed, species. It is described as a semi-arboreal and semi-aquatic frog. The frogs we came upon at the ARRS (which has a population of over 200-300 Golden Frogs) were typically perched on small bushes – on stems and twigs – and on large leaves close to the ground. There was a small disused water-logged paddyfield nearby so the bushes were technically at the edge of a shallow water body. Their IUCN status is Vulnerable.

The frog is small in size — approximately 4 cm from the snout to the vent. The toes are dilated into discs and the middle digit of the toes is longer than the other two. It has three digits on each limb and the webbing is barely noticeable. The skin can be smooth but is often granulated especially on the back due to scattered conical tubercules. The nostril is close to the snout and the tympanum is quite distinct, almost the size of the eye, only slightly smaller.


Hylarana aurantiaca’s distinct feature is a chocolate-brown/olive-green band that runs from the tip of the snout along the flanks to the hindlegs. The eye, nostril and tympanum are all situated on this band. This band is bordered by a bright yellow, almost golden streak running all along the upper border and till the foreleg along the lower border. The back, which is essentially bordered by these two Midas-touched streaks is orange/orange-yellow or olive-brown. The back and the limbs have no barring but for some dark splotches. The eye is black and bulging, the eyelids bright orange. The underparts are creamy white and the skin is a translucent glowing orange when it is lit up by the sun.

Currently, around the world, most of the roughly 5,000 species of frogs are in decline, and we have a very real risk of losing species that are not yet discovered. In India, while 12 new species of tree-frogs were discovered by a team led by S D Biju of Delhi University, Systematics Lab, Delhi, another initiative to re-discover 50 lost amphibians of India (LOST! Amphibians of India Initiative) has yielded just five re-discoveries so far, the prized one being Chalazodes Bubble-nest Frog (Raorchestes chalazodes), unrecorded since 1874. Researchers estimate that we may have lost up to 13% of our amphibians already.

We Ogres cherish the time we spent with the Golden Frogs at ARRS. They were trusting, accessible and — pardon me for anthropomorphising — extremely friendly. It was a privilege to observe and photograph them from so close. The Golden Frog is a lovely representative of a species that has a special place in our hearts – be it as a Frog Prince or as a metaphor in Matsuo Basho’s famous Frog Haiku.

Text and Photographs by Sahastrarashmi
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The Green Ogre – Birds, Wildlife, Ecology and Nature notes from India.

Posted from Agumbe, Karnataka, India.

Encounter: Bicoloured Frog

It’s tiny and blends in completely with the leaf litter but once you spot it, the Bicoloured Frog is unmistakable

The southwest monsoon has just set in and the entire forest is dripping wet. The dimly lit floor is an abstract mosaic of rust, maroon, brown, beige, green and black – leaves in all stages of decomposition, slowly turning into soggy mulch. An occasional vein of green moss on a tree buttress glows iridescent under a rare shaft of sunlight. Fungi sprout everywhere feasting on death and decay. Every tentative footstep encounters leeches – tiny cold-blooded filaments swaying in the stagnant and humid air, relentlessly in the hunt for the iota of warmth that our feet radiate, setting them off on a determined somersaulting advance. Rotting twigs and branches give way at the slightest footfall and the soft murmur of rain on the dense closed canopy is a permanent hum in a forest which is otherwise silent, at least until nightfall provides the cue to lovesick frogs and crickets.

 

We are on the lookout for the Hump-nosed Pit Viper but instead we sight the Bicoloured Frog. It, too, is wet and soaked, motionless until it notices us with its large, round, red eyes, which are well adapted to sight in the semi-darkness of the rainforest. 


True to its name, the predominant impression of the Bicoloured Frog (Clinotarsus curtipes), is the neat division of the colouration of the upper and the lower halves of its body. The upper half (which has been described as grey or brown) is cream-coloured, tinged with yellow resulting in a very light shade of brown that matches the surrounding leaf litter. The lower half of the body is glistening black with no banding on the limbs. Seen in dimmer light the glistening back gives the impression of deep beige. 


The nostrils are very close to the mouth and the tympanum, present on the black half of the body and hence not very easily seen, is as large as the eye. The size is approximately 7 cm and the snout is pointed. The backs of all the four or five frogs that we encountered bore randomly distributed black spots, providing excellent camouflage in the leaf litter. The spotting on the back may or may not be present on individual frogs though all the frogs that we encountered had them.

 

While we photographed the frog – almost lying on the ground for an eye-level view (an act of extreme gallantry considering the omnipresent, ever-flipping thirsty-for-blood leeches) the frog was moderately alarmed and tried to move away, on one occasion walking up using its limbs, but was not unduly shy, never taking more than one hop. Clinotarsus curtipes seemed to be fairly common but none happened to be in breeding colors yet.

 

The IUCN status is Near Threatened, primarily on account of habitat loss. Clinotarsus curtipes is a terrestrial leaf-litter frog but has webbed toes and enters the water only during the breeding season. It adapts well and is found in different forest types — evergreen, semi-evergreen and deciduous. In the breeding season the frog acquires a ruddy disposition with the black receding out from the sides and the underside becoming very dark, almost black. The vocal sac is internal. As in a lot of frog species the female is larger than the male. J C Daniel notes that the dispersal of young frogs is very orderly and almost battalion-like. 
The spots, like the stripes of the tiger, can be distinctive and are used to identify individual frogs during density surveys. The spots are also a good aid to locate the frog since an uncannily well synchronised set of polka dots hopping on the forest floor give away an otherwise excellent camouflage.

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Text and photographs by Sahastrarashmi 


Encounter: Blue-eyed Bush Frog

Blue Eyed Bush Frog

On a dark, wet monsoon night in Agumbe we met the very kissable blue-eyed prince of frogs

Blue Eyed Bush Frog
The Blue-eyed Bush Frog, photographed by Sahastra in Agumbe

A Blue-eyed Bush Frog vocalising with its throat sac puffed out

If the name Philautus neelanethrus does not suggest a blue-blooded prince to you, an audience with the aforesaid certainly will, assuming that you will be granted one. The Blue-eyed Bush Frog inhabits the deep, dense evergreen rainforests of the Western Ghats and was described to science as recently as 2007 from the Sharavathi Valley. 

This diminutive frog, less than 3 cm long, acquires a yellow colouration during the breeding season (though in the picture it appears redder) and has a beautiful golden eye with a horizontal pupil, completely encircled by an iridescent blue ring. It owes its name to this lovely blue eye-ring. It is usually found on mid-height bushes perched on leaves. In the non-breeding season, its colour is creamy.

Our rendezvous with the blue-eyed prince occurred on a wet, rainy night at the Agumbe Rainforest Research Station. We heard the call — one among many enigmatic mating croaks that filled up the inky monsoon night: treek tink-tink-tink. Once located, like a true celebrity, it seemed uncomfortable with the attention and stopped calling. 

After a short break, it called again and we scrambled for a view. I was lucky to get this one shot of the prince before being banished from his august presence. 

Text and photo by Sahastrarashmi 

Excellent pictures of this frog can be viewed at AMOGHAVARSHA and Sharath’s websites.


This post is the first of our Agumbe Diaries. Look out for more about monsoon in the rainforest.


Posted from Agumbe, Karnataka, India.

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